Acute improvement of left ventricular relaxation as a predictor of volume reduction after cardiac resynchronization therapy: a pilot study assessing the value of left ventricular hemodynamic parameter.

Abstract

Cardiac resynchronization therapy (CRT) improves cardiac function, but CRT recipients with advanced heart failure (HF) do not always respond well. Because the best parameters for the prediction of CRT response are not established, we investigated whether improvement of invasive left ventricular (LV) hemodynamic diastolic parameters could identify CRT responders. A total of 34 consecutive patients (age, 69 ± 9 years; 70% men) who received CRT devices for HF were assessed as to whether acute invasive hemodynamic parameters with and without CRT function could predict LV volume responders. These patients demonstrated an improvement in LV dP/dtmax (11.1 ± 11.7%), LV dP/dtmin (4.6 ± 12.1%), and tau (3.7 ± 11.6%) by biventricular pacing. Nineteen patients (55%) were classified as CRT responders, which was defined by a >15% decrease in LV end-systolic volume (ESV) at the 6-month follow-up evaluation. The area under the receiver operator characteristic curve to detect CRT volume response was 0.93 for the shortening of tau, which was superior to any other hemodynamic parameter. The multivariate analysis revealed that this improvement in tau was the strongest predictive factor for identifying CRT volume responders. Of note, the magnitude of tau shortening during biventricular pacing was significantly correlated with the reduction in LVESV at the 6-month follow-up evaluation. The extent of acute improvement in LV isovolumic relaxation time, as assessed by tau, was associated with favorable response to CRT. The assessment of invasive diastolic function could provide valuable information about CRT volume response.